Polaris Vicra Tools; Figure 1-8 Sample Passive Tool - Northern Digital Polaris Vicra User Manual

1.6

Polaris Vicra Tools

The Polaris Vicra System utilizes wireless tools, which may be active or passive. Passive tools
incorporate retro-reflective passive markers and active wireless tools incorporate IRED markers.
The Position Sensor tracks tools based on the geometry of the markers on each tool. The system can
track up to six compatible tools simultaneously and these may include both active wireless and
passive tools.
The Position Sensor requires a tool definition file for each tool. A tool definition file describes a tool
to the Position Sensor (including the tool's marker geometry). The tool definition file for a particular
tool must be loaded from the host computer before the Polaris Vicra System can track that tool.
Note
For more information on tool definition files, see
described in more detail in
Note
For information on tool design and construction, refer to the "Polaris Tool Design Guide".
Passive Tools
Passive tools incorporate NDI passive sphere markers. The passive sphere markers have a retro-
reflective coating that reflects IR light back to its source, instead of scattering it. As such, the IR
light from the Position Sensor illuminators reflects off the markers directly back to the sensors.
Markers can be attached to an object such that the markers are fixed with respect to one another, to
form a tool. The markers must be attached to the object using NDI mounting posts, which are
manufactured to firmly hold NDI spheres. The Polaris Vicra System can track the positions and
orientations of tools, and can also report the positions of individual passive spheres.
An example of a passive tool is shown in
four passive sphere markers.
For more information on passive sphere markers, see
Active Wireless Tools
Active wireless tools incorporate IRED markers that emit IR light. The markers are incorporated in
tools that also house an IR receiver and a (battery) power source. The (previously loaded) tool
definition file identifies it to the system as an active wireless tool.
Polaris Vicra User Guide - Revision 2
"Tool Definition File" on page
"Polaris Vicra System Tools" on page 30.
Figure

Figure 1-8 Sample Passive Tool

Polaris Vicra System Overview
31. Polaris Vicra System tools are
1-8. The example shows a probe that incorporates
"Passive Sphere Markers" on page
Passive Sphere Markers
38.
13